Bone-Cell Growth in Microgravity: Cell biology, Fluid mechanics, and Mass transfer

Prof. P. S. Ayyaswamy

Department of Mechanical Engineering and Applied Mechanics

School of Engineering and Applied Science

University of Pennsylvania, Philadelphia, PA 19104-6315




The total loss our economy incurs every year due to orthopedic ailments is a staggeringly large number, in many billions of dollars. This expense continues to increase, as both the number of procedures expands, as well as life expectancy is extended. National interest in space programs and in establishing space colonies introduces yet another feature related to the above problems. Prolonged exposure of astronauts to microgravity leads to major bone loss. The precise mechanisms causing bone loss are unknown at present. Through the years, different approaches have been used to correct skeletal disorders such as osteoporosis, fracture healing, and cranofacial abnormalities. Of these, biological approaches for repair or replacement of cartilage and bone provide a significant advantage over the use of artificial materials; they become integral parts of the tissue into which they are implanted. In particular, using in vitro synthesized bone tissue with cells aspirated from the patient's marrow is an attractive idea to avoid the limitations of biological and synthetic grafts. During the past several years, we have been addressing several aspects of these issues using experimental and numerical procedures. Our overall objectives have been to (i) formulate conditions which expeditiously produce three-dimensional bone-like tissue cultures in the simulated microgravity environments of NASA designed Rotating wall vessels (RWVs), and (ii) evaluate the effects of microgravity on osteoblast function with respect to bone cell proliferation and cell death. In order to understand bone loss in microgravity, we have now initiated studies of the effects of microgravity on bone cell apoptosis.  In this presentation, these various aspects will be discussed.